The present invention relates to microscope objectives, and more particularly, to an achromatic microscope objective with a numerical aperture of substantially 0.55 having seven components. It is an object of this invention to provide such a microscope objective which is well-corrected for the usual chromatic image aberrations as well as spherical aberration, coma and astigmatism, a 40X magnification in combination with a telescope objective as described in U.S. Pat. No. 3,355,234.
The closest known prior art is U.S. Pat. No. 3,806,231 issued Apr. 23, 1974 to Taira. This patent discloses an objective having seven lenses and a large working distance. The principal differences of the objective of the present invention and reference resides in the prior art objective not providing parallel light exiting the last member of the objective as required by the present objective.